Geology of North America: the Ice Age

Throughout North America's history, glaciers have periodically covered large parts of the continent, known as ice ages. Over the past two million years, four major glaciation periods have been identified, linked to cooler global climates. These ice sheets, sometimes nearly two miles thick, last receded about 10,000 years ago. They shaped the landscape, creating features like the Great Lakes and Niagara Falls, and left behind glacial deposits.

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